I'd imagine some of these things are probably already on the drawing board, since search has gradually been added for issues and so forth (and wiki <<issue 122>> would be Real Soon Now, right? :-)), but I came across an interesting use case to share:
I was actually contacted by a resourceful recruiter who found me on Github. This allowed him to send me targeted opportunities for Python and Ruby work, most of them using progressive practices and distributed SCM, often citing an appreciation for folks who contribute to open source. Pretty cool really, the kind of recruiter I want to keep a relationship with.
I told him about Bitbucket as something to be aware of as well, and he pointed out that there seems to be no easy way to search for users by location, as he can do on Github:
So there. Probably a big request, but site-wide search with lots of metadata and filtering. Go! :-)